Such a device is known from EP 00 52 794. As shown in FIG. 3 of this patent specification, four gears of the standard transmission are shifted mechanically by hand with the manual shift lever 20 from the gearbox according to an H pattern.
Furthermore, via a second gear-shift lever 40, the shifting of two drive gear groups and one reverse drive group takes place.
Such devices, or as shown in FIGS. 1 and 2, with a gear splitting that can be shifted up or down under load of the gears 1 to 4, have proven to be successful in farm tractors.
However, the mechanical two-lever shifting has high space requirements in the driver's cabin, and generally does not satisfy the demands imposed on modern from tractors.